House Republican leaders are proposing a long-term boost to military funding in a bill that would give other federal agencies only a short-term extension of current spending levels, a move that stands to heighten tension with Democrats and complicate plans to keep the government open past Thursday.

House Speaker Paul D. Ryan (R-Wis.) pitched the plan to his GOP colleagues in a closed-door meeting Monday. The bill, set for a vote on Tuesday, would increase Pentagon funding by about $30 billion, to $584 billion, breaking existing spending caps as well as making funding available through September. The rest of the government would continue to be funded at 2017 levels through March 23.

The spending bill would also provide two years of funding for the federal community health center program, which lapsed last year and is at risk of running out of spending authority, and would also extend several other programs.

While House GOP leaders are confident the bill will pass their chamber with Republican votes, it is likely to be dead on arrival in the Senate.

Democrats have refused to sign on to any defense spending increase absent an agreement to bolster nondefense spending alongside it. The budget agreement has also been stalled by unrelated policy disputes, primarily over immigration.

“We want to fund defense, absolutely, but we also want to fund programs that help the middle class, like education, like infrastructure, like scientific research,” Senate Minority Leader Charles E. Schumer (D-N.Y.) said Monday. “We’re standing up and saying we must do both. That’s how this body works.”

The House’s move is calibrated to both appease conservative lawmakers who have become increasingly frustrated at the string of temporary spending measures and to also nudge senators to boost defense funding.

“It’s time for the Senate to take action,” House Majority Whip Steve Scalise (R-La.) said.

Government funding is set to run out Thursday at midnight, and though there were few fears of another shutdown as lawmakers scrambled Monday, the House maneuver stands to inject new uncertainty into the process.

House Republicans plan to pass the spending bill and send it to the Senate on Tuesday, then recess for the week so Democrats can head to Maryland’s Eastern Shore for their yearly policy retreat. But with the Senate unlikely to swallow the House bill, lawmakers could be forced to return to Washington to vote again before the deadline.

The addition of military funding to the temporary spending bill stands to tamp down resistance from members of the House Armed Services Committee, who have pushed fiercely for more Pentagon funding, as well as from the conservative House Freedom Caucus, which typically uses its leverage to issue demands around critical votes.

Rep. Bradley Byrne (R-Ala.), an Armed Services Committee member, said it would have been “difficult” for Republican leaders to cobble together enough GOP votes for another temporary bill, known as a “continuing resolution.”

“One CR after another, at some point you have to say this is not working,” he said.

Rep. Mark Meadows (R-N.C.), the Freedom Caucus chairman, said Monday that the defense funding probably would be enough to win over at least half of the group’s roughly three dozen members. GOP leaders can lose only about 20 votes from their party before they must rely on Democrats to pass legislation, giving the minority leverage to demand concessions.

Democrats blasted the Republicans’ move, arguing that a compromise measure could have gotten votes from both parties.

“They don’t want to work in a bipartisan fashion, and I think it’s the message they’ve been sending for the last 13 months,” House Minority Whip Steny H. Hoyer (D-Md.) said of Republicans. “They want to do it their way or no way.”

Democrats could be forced to curtail their retreat if the Senate, as expected, sends a different bill back to the House.

“We’ll be here to vote,” Hoyer said. “We’ll be here to vote if we need to vote.”

Still unresolved is the issue of protections for undocumented immigrants brought to the United States as minors, known as “dreamers.”

Negotiations on immigration continue, but after forcing a three-day government shutdown last month in an unsuccessful attempt to gain protections for dreamers, Senate Democrats seem to have little appetite to repeat the experience.

They voted to reopen the government after Majority Leader Mitch McConnell (R-Ky.) agreed to allow immigration legislation to be debated on the Senate floor and remain satisfied with that commitment.

“I don’t see a government shutdown coming,” Sen. Richard J. Durbin (D-Ill.), a leader on the immigration issue, said Sunday on CNN’s “State of the Union.” “But I do see a promise by Senator McConnell to finally bring this critical issue that affects the lives of hundreds of thousands of people in America, finally bringing it to a full debate in the Senate.”

Four months into the 2018 fiscal year, Congress has already passed four continuing resolutions that keep government agencies running on last year’s budget levels. The situation particularly infuriates defense hawks, who argue the Pentagon is being deprived of necessary resources.

It’s a mess of Congress’s own making: Lawmakers have been unable to come together around a broader deal to lift budget caps that would otherwise snap into place under a 2011 law that was intended to enforce fiscal discipline in the Capitol.

Legislators are looking at enormous increases for military and domestic spending, but have been squabbling over figures in the tens of billions of dollars as Democrats push for increases for domestic agencies to match what­ever the Pentagon gets.

The immigration issue has complicated the negotiations, with some Democrats resisting a deal on spending until they have achieved protections for dreamers.

Rep. Dennis A. Ross (R-Fla.) said House Republicans have run out of patience with the Senate and want to “impress upon them the significance of funding our defense.”

“I think we have an obligation for the defense of this country to keep doing this, and if it’s a battle of wills, I hope that we will prevail,” he said.

Nonetheless, aides in both parties say a budget deal is in reach and could be finalized as soon as this week. Once that’s in place, the spending committees could get to work writing the actual legislation funding the government through Sept. 30.

Passage of that bill would probably get thrown together with several other must-do items awaiting action on Capitol Hill. Those including an $80 billion-plus disaster aid package for victims of last year’s deadly hurricanes and wildfires and an increase in the government’s borrowing limit.

That deadline on the debt ceiling now looms sometime in the first half of March, according to the Congressional Budget Office, which recently announced it anticipated lower tax revenue because of the new tax law, meaning the government would reach the debt limit sooner than expected.